1. Field of the Invention
The present invention relates to a system for the measurement of three-dimensional shapes and dimensions for maasuring three-dimensional shapes and dimensions in a specific region of an object, for example, for measuring curved shapes or at least one of gap and flushness by means of computing the function (the fitting curve) of an object surface shape or the relative positions of extracted characteristic points.
2. Description of Related Art
As a conventional device for determining the flushness of an object, there is a car sliding roof flushness determination device (Japanese Unexamined Patent Publication 63-61107). It comprises: a laser slit light means for irradiating an infrared laser slit light onto an area extending over the roof part and sliding roof part of a car body; a vision sensor for imaging portions to which the abovementioned laser slit light has been irradiated; and an image processing means wherein the image of the irradiated portion is introduced from the vision sensor and binarized, and, based on the detected amount of divergence of the beam corresponding to the laser slit light in this binarized image, the flushness between the roof part and the sliding roof part is determined.
However, the conventional system had the problem, which had to be solved, that the precision of detection was not sufficient due to the measurement of the flushness by determining the amount of divergence of the beam corresponding to the laser slit light in the binarized image.
Further, hitherto in the production process, dimensional measurements of the flushness and gap of car bodies are performed manually using slide calipers or gap gages. Nevertheless, the former involve discrepancies due to the operator, and even with the same operator there are discrepancies due to the conditions, and the method lacks reliability and there are practical problems which have to be solved. Moreover, in order to perform measurement of the gap or flushness in a specific region of an object and to perform curve fitting to the shape of the object, the XYZ coordinates on the surface of the object are necessary. With measurement of XYZ coordinates in the conventional contact system or spot light system, many points have to be measured in order to measure the precise gap and flushness of an object or to fit curves to the surface shape, and this had the disadvantage that it took time. Further, even in the method using plane object image processing using a slit light, because only the position of the slit light on the image surface (i, j) is obtained, and the XYZ coordinates of the object are not obtained, measurement of the gap and flushness of the object and curve fitting to the surface shape cannot be performed.